#copys.py
class1 = ['zhangsan','lisi','wangwu','zhaoliu']
print('there are {} student in this class:'.format(class1.__len__()))
traverse(class1)
class2 = class1.copy()
class1[0] =('xingjiu') 
traverse(class2)
traverse(class1)

class2 = class1[1:3]   #切片操作
traverse(class2)

class2 = class1[:]
traverse(class2)

class2 = class1[:3]
traverse(class2)

class2 = class1[1:]
traverse(class2)

class2 = class1[3:1:-1]
traverse(class2)


